1. Field of Invention
This invention relates to flame suppressors for gas pipelines.
2. PRIOR ART
A flame front of an undesired reaction may accidentally start to migrate through a pipeline system. The heat transfer conditions may be such that the flame will be quenched by the large amount of residual cooling of the combination of the environment and the pipeline, especially when the pipeline diameter is small. However, in other situations the pipeline may be relatively insulated. If the pipe diameter is large so that the total heat content of the flame front is great, then the pipeline may be heated to a temperature causing the rupture of the pipeline.
Inasmuch as ruptures of pipeline attributable to the advancement of a flame front are relatively rare, and inasmuch as the self-dissipation of a flame front can occur under a variety of conditions, there are a variety of engineering considerations tending to decrease the number of flame arrestors scheduled for installation merely to protect the long runs of a pipeline from rupture. However, the hazards inherent in permitting an advancing flame front to enter a gas processing facility, or a chemical plant, or a gas storage facility, are so serious that there is adequate economic justification for flame arrestors protecting substantially all facilities to which pipeline gas might be delivered, notwithstanding the infrequency of such accidents. If a flame front enters either end of a flame arrestor, the cooling is designed to be adequate to quench the flame before the flame front can advance to the other end of the flame arrestor. Moreover, the flame arrestor is advantageously designed to quench two flame front separator in time by less than an hour or only a few seconds.
Preferred embodiments of the invention of said Ser. No. 860,791 feature a deep pool of heat transfer liquid, in the a lower portion of which an array of heat transfer tubes serve to cool the divided gas stream flowing therethrough. Even if the one or more flame fronts involve significant heat, the cooling capacity of the liquid is sufficient to quench each flame front advancing into the reaction boundary suppressor system of said Ser. No. 860,791.
In the normal flow of gas, the provision of conical plenum zones is generally acceptable even though there are potentialities for relatively rapid changes in the cross-sectional area of a gas stream in the transition between systems having different cross-sectional areas. In research relating to the development of the flame arrestor of the present invention, the surprising discovery was made that flame front compositions and/or compositions closely approaching those of a flame front could undergo erratic modifications and stabilization was subjected to a large plenum. Such discovery during the development of the present invention was surprising inasmuch as many varieties of equipment had directed gas streams through appropriate plenums and zones of rapid change in the cross-sectional area without troublesome unreliability.